An observational study in Conjunctivitis, Allergic, sponsored by Instituto de Oftalmología Fundación Conde de Valenciana. Active, not recruiting at 1 site in Mexico. Open to participants aged 5 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-04.
Sponsored by Instituto de Oftalmología Fundación Conde de Valenciana · Observational
Allergic conjunctivitis (AC) causes inflammation of the conjunctiva in response to environmental allergens, affecting a significant percentage of the world population and reducing quality of life. The pathophysiology is poorly understood, lacking effective treatments. MicroRNAs have potential for diagnosing and characterizing inflammatory diseases. This study aims to compare the expression profiles of inflammation-regulating microRNAs (miR-19, miR-23, miR-125b, miR-146a, and miR-155) in serum and tear samples from subjects with AC and healthy subjects to identify biomarkers and therapeutic targets.
Allergic conjunctivitis (AC) is an inflammatory disorder of the conjunctiva triggered by exposure to environmental allergens. This ocular condition affects a significant proportion of the global population, leading to a reduction in quality of life and, in some cases, visual impairment. The pathophysiology of AC remains poorly understood, and effective targeted therapies are limited. MicroRNAs have emerged as promising tools for the diagnosis and characterization of inflammatory diseases such as asthma and rhinitis; however, studies evaluating microRNA involvement in allergic conjunctivitis are scarce. Therefore, identifying microRNAs that are differentially regulated in AC is essential to better understand disease pathogenesis and to explore potential biomarkers and therapeutic targets.
This study aims to determine whether differences exist in the expression profiles of inflammation-regulatory microRNAs between subjects with allergic conjunctivitis and healthy controls. The working hypothesis is that subjects with allergic conjunctivitis exhibit differential expression of inflammation-related microRNAs compared with healthy individuals.
An observational cross-sectional study will be conducted including subjects aged 5 to 30 years with a clinical diagnosis of allergic conjunctivitis, as well as age-matched healthy controls. Tear samples and peripheral blood samples for serum isolation will be collected from all participants. Total RNA will be extracted from both sample types, and the expression of miR-19, miR-23, miR-125b, miR-146a, and miR-155 will be quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Relative expression levels (fold change) will be calculated in the allergic conjunctivitis group and compared with those observed in healthy controls to identify microRNAs specifically associated with the disease. Receiver operating characteristic (ROC) curve analysis will be performed to evaluate the potential of the studied microRNAs as diagnostic biomarkers.
210 studies on the registry are indexed under Conjunctivitis, Allergic; 18 are open to participants now.
This study's planned enrollment of 40 is below the median of 107 across 28 observational studies indexed under Conjunctivitis, Allergic.
Browse Conjunctivitis, Allergic studies →Instituto de Oftalmología Fundación Conde de Valenciana is the lead sponsor of 45 studies on the registry; 10 are open to participants now.
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The study population will include subjects aged 5 to 30 years with a clinical diagnosis of allergic conjunctivitis, as well as age-matched healthy controls. Participants will be recruited from a specialized ophthalmology center. Subjects with allergic conjunctivitis must present active ocular symptoms at the time of enrollment, while healthy controls must have a clinically normal ocular surface and no history of active ocular disease. All participants or their legal guardians will provide written informed consent, with assent obtained from minors when applicable.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Healthy Controls:
Exclusion Criteria
Healthy Controls:
-History of infectious disease within 2 months prior to sample collection.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Subjects aged 5 to 30 years with a confirmed clinical diagnosis of allergic conjunctivitis (Seasonal, Perennial, or Vernal Keratoconjunctivitis). Participants must present active symptomatology and positive skin prick tests corresponding to the allergic condition.
Clinically healthy subjects aged 5 to 30 years with a normal ocular surface evaluation. Participants must have no personal history of allergic diseases (ocular or systemic), no active ocular infection, and no chronic-degenerative or autoimmune diseases.
Expression of inflammation-regulatory microRNAs in tear samples
Relative expression (fold change) of miR-19, miR-23, miR-125b, miR-146a, and miR-155 in tear samples measured by quantitative real-time polymerase chain reaction (qRT-PCR) and calculated using the 2\^-ΔΔCT method.
Time frame: Baseline
Expression of inflammation-regulatory microRNAs in serum samples
Relative expression (fold change) of miR-19, miR-23, miR-125b, miR-146a, and miR-155 in serum samples measured by quantitative real-time polymerase chain reaction (qRT-PCR) and calculated using the 2\^-ΔΔCT method.
Time frame: Baseline
Diagnostic performance of candidate microRNAs
Evaluation of the diagnostic potential of miR-19, miR-23, miR-125b, miR-146a, and miR-155 through receiver operating characteristic (ROC) curve analysis, including area under the curve (AUC).
Time frame: Baseline
Plan to share: No
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This study is active, not recruiting, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Instituto de Oftalmología Fundación Conde de Valenciana